Spaced taste avoidance conditioning in Lymnaea

Takigami, Satoshi; Sunada, Hiroshi; Lukowiak, Ken; Sakakibara, Manabu

doi:10.1016/j.nlm.2013.10.022

Cited by 15 publications

(7 citation statements)

References 60 publications

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“…Here, we look at the ability of Lymnaea to learn and remember for many days not to respond to a food substance that normally elicits a feeding response. This is referred to as conditioned taste aversion (CTA) (Ito et al, , 2012Kawai et al, 2004;Sugai et al, 2006;Takigami et al, 2014). To produce a CTA, an appetitive stimulus, such as sucrose [the conditioned stimulus (CS)], is repeatedly paired with an aversive stimulus, such as an electric shock [the unconditioned stimulus (US)] Ito et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Memory block: A consequence of conflict resolution

Ito

Yamagishi

Hatakeyama

et al. 2015

Journal of Experimental Biology

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Food deprivation for 1 day in the pond snail Lymnaea stagnalis before aversive classical conditioning results in optimal conditioned taste aversion (CTA) and long-term memory (LTM) formation, whereas 5-day food deprivation before training does not. We hypothesize that snails do in fact learn and form LTM when trained after prolonged food deprivation, but that severe food deprivation blocks their ability to express memory. We trained 5-day food-deprived snails under various conditions, and found that memory was indeed formed but is overpowered by severe food deprivation. Moreover, CTA-LTM was context dependent and was observed only when the snails were in a context similar to that in which the training occurred.

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Section: Introductionmentioning

confidence: 99%

Memory block: A consequence of conflict resolution

Ito

Yamagishi

Hatakeyama

et al. 2015

Journal of Experimental Biology

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“…The pond snail Lymnaea stagnalis is an excellent model system to elucidate the causal neuronal mechanisms underlying learning and the formation of memory Otsuka et al, 2013;Takahashi et al, 2013;Lukowiak et al, 2014;Takigami et al, 2014). Here, we focus our attention on aversive conditioning of feeding behavior known as conditioned taste aversion.…”

Section: Introductionmentioning

confidence: 99%

The Yerkes-Dodson law and appropriate stimuli for conditioned taste aversion in Lymnaea

Ito

Yamagishi

Takigami

et al. 2014

Journal of Experimental Biology

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The pond snail Lymnaea stagnalis can learn conditioned taste aversion and then consolidate it into long-term memory (LTM). A high-voltage electric shock was used as the unconditioned stimulus, where we have previously used KCl. We varied the strength of both the conditioned and unconditioned stimuli to determine whether the so-called Yerkes-Dodson law prevailed. This is an empirical relationship between the state of arousal and LTM formation, showing that there is an optimal level of arousal leading to memory formation. However, too little or too much arousal results in poorer LTM. We found here that the most appropriate stimuli to use in taste aversion training in Lymnaea were a 10 mmol l −1 sucrose solution as the conditioned stimulus and a 3 s electric shock as the unconditioned stimulus.

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“…This topic of why some snails do not form LTM is not dwelt on but we might possibly learn more about the causal neuronal mechanisms underlying LTM by studying those that do not form LTM. Regarding the mechanisms of LTM formation, our recent studies indicated that a space training procedure where there is an interposition of a couple of hours between CS-US paired presentations effectively enhances the formation of LTM 11 , 13 . Depending on the criteria used the percentages of good vs. poor performers can vary greatly.…”

Section: Discussionmentioning

confidence: 99%

Electrophysiological characteristics of feeding-related neurons after taste avoidance Pavlovian conditioning in Lymnaea stagnalis

et al. 2014

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Taste avoidance conditioning (TAC) was carried out on the pond snail, Lymnaea stagnalis. The conditional stimulus (CS) was sucrose which elicits feeding behavior; while the unconditional stimulus (US) was a tactile stimulus to the head which causes feeding to be suppressed. The neuronal circuit that drives feeding behavior in Lymnaea is well worked out. We therefore compared the physiological characteristics on 3 classes of neurons involved with feeding behavior especially in response to the CS in conditioned vs. control snails. The cerebral giant cell (CGC) modulates feeding behavior, N1 medial neuron (N1M) is one of the central pattern generator neurons that organizes feeding behavior, while B3 is a motor neuron active during the rasp phase of feeding. We found the resting membrane potential in CGC was hyperpolarized significantly in conditioned snails but impulse activity remained the same between conditioned vs. control snails. There was, however, a significant increase in spontaneous activity and a significant depolarization of N1M’s resting membrane potential in conditioned snails. These changes in N1M activity as a result of training are thought to be due to withdrawal interneuron RPeD11 altering the activity of the CGCs. Finally, in B3 there was: 1) a significant decrease in the amplitude and the frequency of the post-synaptic potentials; 2) a significant hyperpolarization of resting membrane potential in conditioned snails; and 3) a disappearance of bursting activity typically initiated by the CS. These neuronal modifications are consistent with the behavioral phenotype elicited by the CS following conditioning.

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Spaced taste avoidance conditioning in Lymnaea

Cited by 15 publications

References 60 publications

Memory block: A consequence of conflict resolution

Memory block: A consequence of conflict resolution

The Yerkes-Dodson law and appropriate stimuli for conditioned taste aversion in Lymnaea

Electrophysiological characteristics of feeding-related neurons after taste avoidance Pavlovian conditioning in Lymnaea stagnalis

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